In its simplest form, direct observation of responses, such as cytopathic changes induced by virus infections, has been used historically to screen for viruses in cell culture. Confirmatory assays for specific pathogen identification depend on neutralization assays or complex molecular methods that use biological and chemical probes depending on the signals to be detected. These assays are generally elaborate, and require specific reagents and complex methods usually requiring a range of two hours to weeks where there is sufficient material for detection, or up to months when there is not. Measurement of cellular and/or humoral responses to stimuli is also very useful for the identification of normal immune responses or, alternatively, disease or infection states. Cellular and humoral responses engage immediately after immune defenses detect a foreign agent, a stimulant, an antibody, or a pathogen. Devices and methods are needed that can directly detect these responses as they occur, particularly at the cellular level.